DIRECTIONALITY CONCEPTS FOR OVERCURRENT RELAY APPLICATIONS

Applications of optical fiber in relay protection

Because relay protection plays a significant role in the entire power system, optical fiber communication is generally used as the physical transmission channel of the relay protection device to protect the signal. In this paper, the main technology of optical differential protection, in the process of 6 KV power distribution system reform is how to apply this situation are introduced in detail, at the same time, a detailed description of the relative performance for the optical fiber differential protection. Optical fibre measurement is advancing, vari ous techniques in optical signal pro cessing are still under development and therefore there is still much research to be carried out into the applicability to the power industry.

Relay protection instantaneous overcurrent protection setting

IOCP settings depend on maximum short-circuit current and protection coverage, following IEC 60909 (short-circuit current calculation) and IEC 60255-151 (overcurrent protection settings). maxIi setting allows normal transient overcurrent inrush current for transformers: A 1st peak 10 to 25 x In Motor direct on line starting current: NOTE: MasterPacT MTZ1 L1 type circuit breakers are equipped with an additional fast instantaneous trip set at 10 x In. Overcurrent protection relay settings are critical for any electrical distribution system. The ANSI device number is 50 for an instantaneous overcurrent (IOC) or a Definite Time overcurrent (DTOC) and 51 for the Inverse Definite Minimum Time.

The hallmark of the development of relay protection is

The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current,, reverse flow, over-frequency, and under-frequency. Protection relays have shaped the way engineers approach relay protection and electrical safety. They are intended to quickly identify a fault and isolate it so the balance of the system continue to run under normal conditions.